Network Working Group Z. Li Internet-Draft L. Zhang Intended status: Standards Track Huawei Technologies Expires: January 4, 2015 G. Yang China Telecom July 3, 2014 RSVP-TE Extensions for Bit Error Rate (BER) Measurement draft-zhang-ccamp-rsvpte-ber-measure-02 Abstract In the mobile backhaul network, the mobile service is sensitive to Bit Error Rate (BER). When the BER value of the service exceeds the threshold, the cell site equipments will stop working and the mobile terminal users cannot obtain voice and data services anymore. Now the mobile backhaul tends to be IP/MPLS network and MPLS TE LSP is used to bear the mobile service which may be encapsulated in PW or L3VPN end to end. Then the ingress Label Switched Router (LSR) of the MPLS TE LSP needs to get information on BER along the path of the LSP. This document proposes new extensions of RSVP-TE to advertise the BER measurement requirement of the specific LSP to all of the transit LSRs and the egress LSR, and to report the BER measurement result from any transit or egress LSR towards the ingress LSR. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119]. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on January 4, 2015. Li, et al. Expires January 4, 2015 [Page 1] Internet-Draft RSVP Extensions for BER Measurement July 2014 Copyright Notice Copyright (c) 2014 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. BER_REQUEST TLV . . . . . . . . . . . . . . . . . . . . . . . 3 3.1. Format of BER_REQUEST . . . . . . . . . . . . . . . . . . 3 3.2. Procedures for BER_REQUEST TLV . . . . . . . . . . . . . 5 4. BER Measurement Result Report . . . . . . . . . . . . . . . . 5 4.1. Error Code for BER measurement report . . . . . . . . . . 5 4.2. Procedures for BER Error Code . . . . . . . . . . . . . . 6 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 6. Security Considerations . . . . . . . . . . . . . . . . . . . 6 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 7.1. Normative References . . . . . . . . . . . . . . . . . . 6 7.2. Informative References . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 1. Introduction Bit Error Rate (BER) is a significant parameter for the mobile service, which can cause the cell site equipment to stop working when its value exceeds the threshold that the mobile service can tolerate. In IP/MPLS based mobile backhaul network, PW and L3VPN are adopted to bear the mobile service, and MPLS TE LSP is adopted as the transport tunnel for which Hot-standby (MPLS TE HSB) or fast reroute (MPLS TE FRR) technologies is used to meet the SLA(Service Level Agreement). There are different kinds of failure detection methods, such as BFD[RFC5884] or MPLS OAM[RFC4378], to trigger fast traffic switch when failure happens. But as to BER, even if the BER value exceeds the threshold, the detection mechanisms may be not able to detect the failure to trigger traffic switch to the backup path. In order to solve the issue, RSVP-TE extensions can be introduced to notify the ingress LSR of the BER measurement result when a specific LSR along Li, et al. Expires January 4, 2015 [Page 2] Internet-Draft RSVP Extensions for BER Measurement July 2014 the LSP detects that the BER value exceeds the threshold or restores to the normal value below the threshold. When the ingress LSP receives the BER measurement result, it can switch the traffic between the primary path and the backup path which is policy specific and out of scope of the document. This document defines new extensions of RSVP-TE for BER measurement: One extension is to advertise the BER measurement requirement to all of the transit LSRs and the egress LSR, then these LSRs along the path will start BER measurement for the LSP. The other extension is to report the BER measurement result from any transit LSR or the egress LSR towards the ingress LSR. 2. Terminology BER: Bit Error Rate RAN: Radio Access Network LSR: Label Switch Router LSP: Label Switch Path 3. BER_REQUEST TLV 3.1. Format of BER_REQUEST Path Message of RSVP-TE is used to signal the BER measurement requirement of the LSP, and the LSP_ATTRIBUTES object will be included in the Path Message. The LSP_ATTRIBUTES object which is defined in [RFC5420] is used to signal attributes required in support of an LSP, or to indicate the nature or use of an LSP. The LSP_ATTRIBUTES object format is as below (refer to[RFC5420]): LSP_ATTRIBUTES class = 197, C-Type = 1 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | // Attributes TLVs // | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: LSP_ATTRIBUTES object The LSP_ATTRIBUTES object class is 197 of the form 11bbbbbb. This C-Num value (see [RFC2205], Section 3.10) ensures that LSRs that do Li, et al. Expires January 4, 2015 [Page 3] Internet-Draft RSVP Extensions for BER Measurement July 2014 not recognize the object pass it on transparently. One C-Type is defined, C-Type = 1 for LSP Attributes. The Attributes TLVs are encoded as below: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | // Value // | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2: Attributes TLVs format Here we define the BER_REQUEST TLV which is a new type of Attribute TLV to indicate the BER measurement requirement of the LSP. The format of BER_REQUEST TLV is as below: LSP_ATTRIBUTES Class=197, C-Type=1 Type=TBD, BER_REQ TLV 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = BER_REQ TLV(TBD) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | BER threshold | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3:BER_REQUEST TLV Type The identifier of the BER_REQUEST TLV which should be allocated by IANA. Length Indicates the total length of the TLV in two octets. Value The BER threshold for the service. It is a 32-bit IEEE floating point number. The format of IEEE floating-point numbers is further summarized in [RFC1832]. Li, et al. Expires January 4, 2015 [Page 4] Internet-Draft RSVP Extensions for BER Measurement July 2014 3.2. Procedures for BER_REQUEST TLV BER_REQUEST TLV is one type of attribute TLVs of the LSP_ATTRIBUTE object. It is optional and MAY be placed in Path messages to advertise the BER measurement requirement of the LSP. The process of the LSP_ATTRIBUTE object can refer to section 4.2 in [RFC5420]. When a RSVP-TE LSP requires the BER measurement of the path, the ingress LSR MUST send a Path Message with BER_REQUEST TLV in which the BER threshold value is set according to the service requirement. When an LSR receives a Path Message with the BER_REQUEST TLV, the LSR SHOULD start the BER measurement for the LSP. The LSR MUST pass the Path Message with BER_REQUEST TLV unchanged to the next LSR. If the measured BER value exceeds the BER threshold value set in the BER_REQUEST TLV, the LSR MUST report the bit error result towards the ingress LSR of the LSP. If an LSR cannot support the BER_REQUEST TLV, the LSR SHOULD ignore this TLV and pass the Path Message with BER_REQUEST TLV unchanged to the next LSR. For an LSR which has started the BER measurement on receiving the Path Message with the BER_REQUEST UEST TLV, if the LSR receives the updated Path Message without BER_REQUEST TLV, it MUST stop the BER measurement for this LSP and pass the Path Message unchanged to the next LSR. 4. BER Measurement Result Report For an LSR that starts the BER measurement, When the BER measurement value exceeds the threshold for the service, the LSR MUST report the indication of bit error towards the ingress LSR of the LSP. If the LSR has already reported the indication of bit error, it MUST report the elimination of bit error towards the ingress LSR when it measures that the BER is blow the specified threshold. A new type of Error Code and its Error Value of the ERROR_SPEC object are defined to report the BER measurement result within PathErr Message. 4.1. Error Code for BER measurement report The ERROR_SPEC object is defined in [RFC2205] and [RFC3209]. The BER Error Code and its Error Values are defined as below: Error Code Error Value Description ----------------------------------------------------------------- TBD 0 Bit Error Elimination 1 Bit Error Indication Li, et al. Expires January 4, 2015 [Page 5] Internet-Draft RSVP Extensions for BER Measurement July 2014 4.2. Procedures for BER Error Code The BER measurement result is reported through a new Error Code and the corresponding Error Value of the ERROR_SPEC object which is placed in PathErr Message. For a LSR which has started the BER measurement for the specific LSP, if the BER measurement value exceeds the threshold of the service, a PathErr Message MUST be sent towards the ingress LSR of this LSP. The PathErr Message MUST include an ERROR_SPEC object with the BER Error code and Error Value 1 for Bit Error Indication. When the BER measurement value becomes less than the BER threshold value after report the Bit Error Indication, the LSR MUST send a PathErr Message including an ERROR_SPEC object with the BER Error Code and Error Value 0 for Bit Error Elimination. 5. IANA Considerations IANA should allocate the type value of the BER_REQUEST TLV and the BER Error Code which are defined in this document. 6. Security Considerations The extensions of RSVP TE for BER in this document do not introduce any new security issues, and the reader is referred to the security considerations expressed in [RFC2205], [RFC3209], and [RFC5420]. 7. References 7.1. Normative References [RFC1832] Srinivasan, R., "XDR: External Data Representation Standard", RFC 1832, August 1995. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2205] Braden, B., Zhang, L., Berson, S., Herzog, S., and S. Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1 Functional Specification", RFC 2205, September 1997. [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP Tunnels", RFC 3209, December 2001. Li, et al. Expires January 4, 2015 [Page 6] Internet-Draft RSVP Extensions for BER Measurement July 2014 [RFC5420] Farrel, A., Papadimitriou, D., Vasseur, JP., and A. Ayyangarps, "Encoding of Attributes for MPLS LSP Establishment Using Resource Reservation Protocol Traffic Engineering (RSVP-TE)", RFC 5420, February 2009. 7.2. Informative References [RFC4378] Allan, D. and T. Nadeau, "A Framework for Multi-Protocol Label Switching (MPLS) Operations and Management (OAM)", RFC 4378, February 2006. [RFC5884] Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow, "Bidirectional Forwarding Detection (BFD) for MPLS Label Switched Paths (LSPs)", RFC 5884, June 2010. Authors' Addresses Zhenbin Li Huawei Technologies Huawei Bld., No.156 Beiqing Rd. Beijing 100095 China Email: lizhenbin@huawei.com Li Zhang Huawei Technologies Huawei Bld., No.156 Beiqing Rd. Beijing 100095 China Email: monica.zhangli@huawei.com Guangming Yang China Telecom No. 109, Zhongshan Road West, Tianhe District Guangzhou 510630 China Email: yanggm@gsta.com Li, et al. Expires January 4, 2015 [Page 7]